package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import io.lettuce.core.Consumer;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.MapRecord;
import org.springframework.data.redis.connection.stream.ReadOffset;
import org.springframework.data.redis.connection.stream.StreamOffset;
import org.springframework.data.redis.connection.stream.StreamReadOptions;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author YJY
 * @since 2025-03-11
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedissonClient redissonClient;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;//查看继承关系的快捷键
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }


    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    //类初始化完毕就执行
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }



//    private class VoucherOrderHandler implements Runnable {
//        String queueName = "streams.order";
//        @Override
//        public void run() {
//            while(true) {
//                try {
//                    //1.获取队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.order >
//                    List<MapRecord<String,Object,Object>> list = stringRedisTemplate.opsForStream().read(
//                            Consumer.from("g1","c1"),
//                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
//                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
//                    );
//                    //2.判断消息获取是否成功
//                    //2.1 如果获取失败 说明没有消息 继续下一次循环
//
//                    //2.2 如果获取成功,可以下单
//
//                    //3. 如果获取成功,可以下单
//
//                    //4.ACK确认
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常",e);
//                }
//            }
//        }
//    }

    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1204*1024);
    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while(true) {
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3.获取锁
        boolean isLock = lock.tryLock();//默认不等待 立刻返回 失败不等待
        //4.判断是否获取锁成功
        if(!isLock){
            //获取锁失败,返回错误或重试
            log.error("不允许重复下单");
            return;
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        }finally {
            lock.unlock();
        }
    }
    private IVoucherOrderService proxy;


    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行Lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );

        //2.判断结果是否为0
        int r = result.intValue();
        if(r != 0){
            //2.1 不为0,代表没有购买资格
            return Result.fail(r==1?"库存不足":"不能重复下单");
        }
        //2.2 为0 有购买资格,把下单信息 保存到阻塞队列
        VoucherOrder voucherOrder = new VoucherOrder();
//        long orderId = redisIdWorker.nextId("order");
        //2.3 订单ID

        voucherOrder.setId(orderId);
        //2.4 用户ID
        voucherOrder.setUserId(userId);
        //2.5 代金券ID
        voucherOrder.setVoucherId(voucherId);
        //2.6 放入阻塞队列
        orderTasks.add(voucherOrder);

        //3. 获取代理对象
        // 获取代理对象(事务)
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //4.返回订单id
        return Result.ok(orderId);
    }


//    public Result seckillVoucher(Long voucherId) {
//        //获取用户
//        Long userId = UserHolder.getUser().getId();
//        //1.执行Lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(), userId.toString()
//        );
//
//        //2.判断结果是否为0
//        int r = result.intValue();
//        if(r != 0){
//            //2.1 不为0,代表没有购买资格
//            return Result.fail(r==1?"库存不足":"不能重复下单");
//        }
//        //2.2 为0 有购买资格,把下单信息 保存到阻塞队列
//        VoucherOrder voucherOrder = new VoucherOrder();
////        long orderId = redisIdWorker.nextId("order");
//        //2.3 订单ID
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        //2.4 用户ID
//        voucherOrder.setUserId(userId);
//        //2.5 代金券ID
//        voucherOrder.setVoucherId(voucherId);
//        //2.6 放入阻塞队列
//        orderTasks.add(voucherOrder);
//
//        //3. 获取代理对象
//        // 获取代理对象(事务)
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//
//        //4.返回订单id
//        return Result.ok(orderId);
//    }


//    public Result seckillVoucher(Long voucherId) {
//        //1.查询优惠卷
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始!");
//        }
//        //3.判断秒杀是否已经结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束!");
//        }
//
//        //4.判断库存是否充足
//        if (voucher.getStock() < 1) {
//            return Result.fail("库存不足!");
//        }
//
//        Long userId = UserHolder.getUser().getId();
//        //创建锁对象
////        SimpleRedisLock simpleRedisLock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//
//        //获取锁
//        boolean isLock = lock.tryLock();//默认不等待 立刻返回 失败不等待
//        //判断是否获取锁成功
//        if(!isLock){
//            //获取锁失败,返回错误或重试
//            return Result.fail("请勿重复下单!");
//        }
//        //synchronized (userId.toString().intern()) {
//
//        try {
//            // 获取代理对象(事务)
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);//  事务失效
//            // }
//        }finally {
//            lock.unlock();
//        }
//    }

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单
        Long userId = UserHolder.getUser().getId();


        //5.1查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //5.2判断是否存在
        if(count > 0){
            //用户已经购买过了
            log.error("您已经买过一次了");
        }

        //6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1") //CAS compare and set 成功率太低!
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0) // where id = ? and stock > 0
                .update();

        if (!success) {
            log.error("库存不足!");
        }

        //7.创建订单

        save(voucherOrder);

    }
}
